The reinforcement of rubber by carbon black

Recent research on the carbon reinforcement of rubber is reviewed and existing theories examined. The stiffening effect of carbon black is thought to be little influenced by the size of the individual spherical particles, but values of tensile strength, tear strength, and abrasion resistance increase with decreasing particle size of the black. Departures from this generalization are considered and possible factors discussed. The nature of the attachments between carbon particles and rubber molecules forms the subject of much current research, the results of some of which indicate the possibility that chemical cross linkages supplement physical adsorption at the carbon-rubber interface.